Definition of Favourable Conservation Status for Purple Moor-Grass
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Definition of Favourable Conservation Status for Purple Moor-grass & Rush Pastures Defining Favourable Conservation Status Project Author: Richard G. Jefferson www.gov.uk/natural-england Acknowledgements I would like to thank the following people for their contributions to the production of this document: Hannah Gibbons and Steve Payne at Devon Wildlife Trust, Mary-Rose Lane at Environment Agency, Helen Doherty at SNH and Stuart Smith at NRW. Andy Brown, Catherine Burgess, Iain Diack, Jeff Edwards, Michael Knight, Sally Mousley, Clare Pinches, Keith Porter and the Defining Favourable Conservation Status team at Natural England. 1 Contents About the DFCS project……………………………………………………………………………………….. 3 Introduction……………………………………………………………………………………………………... 4 Definition and ecosystem context…………………………………………………………………………….. 6 Metrics and attribute…………………………………………………………………………………………… 9 Evidence……………………………………………………………………………………………………….. 10 Conclusions…………………………………………………………………………………………………… 17 Annex 1: References…………………………………………………………………………………………. 19 2 About the DFCS project Natural England’s Defining Favourable Conservation Status (DFCS) project is defining the minimum threshold at which habitats and species in England can be considered to be thriving. Our FCS definitions are based on ecological evidence and the expertise of specialists. We are doing this so we can say what good looks like and to set our aspiration for species and habitats in England, which will inform decision making and actions to achieve and sustain thriving wildlife. We are publishing FCS definitions so that you, our partners and decision-makers can do your bit for nature, better. As we publish more of our work, the format of our definitions may evolve, however the content will remain largely the same. This definition has been prepared using current data and evidence. It represents Natural England’s view of FCS based on the best available information at the time of production. 3 Introduction This document sets out Natural England’s view on Favourable Conservation Status (FCS) for Purple moor-grass and rush pastures in England. FCS is defined in terms of three parameters: natural range and distribution, area, and structure and function attributes. Section 2 provides the summary definition of FCS in England. Section 3 covers contextual information, section 4 the metrics used and section 5 describes the evidence considered when defining FCS for each of the three parameters. Section 6 sets out the conclusions on favourable values for each of the three parameters. Annex 1 lists the references. This document does not include any action planning, or describe actions, to achieve or maintain FCS. These will be presented separately, for example within strategy documents. The guidance document Defining Favourable Conservation Status in England describes the Natural England approach to defining FCS. 2. FCS in England Purple moor-grass & rush pastures is a widespread but localised habitat of high biodiversity value occurring throughout the English lowlands and along the upland fringe wherever there are suitable substrates and hydrological regimes. It is normally maintained by extensive grazing by livestock. The extent of this type of grassland has declined significantly over the last 100 years although its overall range has remained stable. Its vulnerability to climate change has been assessed as medium and, like other semi-natural grasslands, it provides important ecosystem services. The habitat will achieve FCS when the structural and functional attributes set out in section 6.3 are met over 95% of the favourable area. This includes attributes relating to floristic composition, patterns of vegetation zonation and transitions, cover of undesirable species, sward structure, soil and water nutrient and pH status, hydrological regime, grazing management and parcel size and connectivity. In particular, to achieve FCS the vegetation should be broadly typical of the relevant plant communities and their species composition. There should be some bare ground and variation in sward height including scattered scrub of various age classes. The soils should have properties typical of the habitat notably low soil P and a pH in the range 4.7 to 7.4. Surface water or groundwater status should normally be oligotrophic and the hydrological regime should provide a sub-surface water table during the summer and a winter water table ± at the surface with inundation absent or only to a minor degree in winter. The habitat should be grazed by livestock usually at an average annual density of c. 0.4 LU/ha/year, depending on site productivity and conservation objectives. There should be at least some contiguous or connected areas of suitable semi-natural habitat. The attainment of favourable status will require an increase in the current extent of the habitat by approximately 65,000 ha (c.620 % above baseline of c.10,500 ha) distributed throughout the range of the habitat and the maintenance of its current range and distribution. 4 FCS parameter Favourable status Confidence in the parameter Range and The habitat is widely but discontinuously High distribution distributed in England with concentrations in south-west England, East Anglia and northern England. Potentially, the whole of England is able to support the habitat where suitable hydrological regimes and edaphic conditions exist. Area Purple moor-grass and rush pasture - 76,000 ha Moderate Note – Figures Annex I Molinia meadows - 18,000 ha rounded to nearest 1000 ha Structure and At least 95% of the favourable area of the habitat Low function should meet the structure and function requirements. As at March 2020, based on a comparison of the favourable values with the current values, purple moor-grass and rush pastures are not in favourable conservation status. Note, this conclusion is based solely on the information within this document not on a formal assessment of status nor on focussed and/or comprehensive monitoring of status. 5 Definition and ecosystem context 3.1 Habitat definition and status The purple moor-grass and rush pastures Priority Habitat (PMGRP) consists of five individual NVC communities: M22 Juncus subnodulosus-Cirsium palustre fen-meadow. A highly variable species-rich rush- dominated vegetation which occurs on wet, base-rich peats and mineral soils in lowland Great Britain with notable concentrations in the chalk river valleys of south and eastern England. The majority of stands occupy more or less flat situations or hollows but a large number occur on seepage slopes. In base-rich mesotrophic-eutrophic conditions they can cover spring mounds. M23 Juncus effusus/acutiflorus-Galium palustre rush-pasture is widespread on wet, moderately acid to neutral peaty and mineral soils primarily in the cool and wet lowlands and upland fringes of northern and western Britain. The M23a Juncus acutiflorus sub-community is typically more species-rich than the M23b Juncus effusus sub-community. The latter is often the product of attempts to agriculturally improve marshy grasslands by drainage, nutrient addition and possibly re-seeding. M24 Molinia caerulea – Cirsium dissectum fen-meadow is the more widespread and diverse community. It is characteristic of moist base-rich to mildly acidic soils in the lowlands of England and Wales. It comprises a heathy form found mainly in south Wales, south-west England and Northern Ireland, a form with tall herbs mainly in the fen systems of East Anglia, and a more widespread ‘typical’ form widely but locally distributed in southern Britain. Some forms of Molinia – Cirsium fen-meadow with abundant Cladium are referable to Annex I type 7210 Calcareous fens with Cladium mariscus and species of the Caricion davallianae. M25 Molinia caerulea - Potentilla erecta mire is considered as a floristically-impoverished degraded bog community. However more-species rich forms of M25 occur, particularly in the lowlands, and may co-occur in complex, intimate mosaics with M24 and may be difficult to distinguish from the latter (e.g. New Forest). M26 Molinia caerulea – Crepis paludosa A very rare community occurring on moist, moderately base-rich peats and peaty mineral soils in England, Wales and Scotland with a stronghold in the sub-montane northern Pennines. A scatter of small sites occur in north Wales. The vegetation has a distinctive sub-montane character, manifested in the presence of species with a northern distribution, such as marsh hawk’s-beard Crepis paludosa and globe-flower Trollius europaeus. The Festuca rubra sub-community often occurs on banks in enclosed meadows and pastures in association with MG3 and U4c. The Sanguisorba officinalis sub-community is more usually found in transitional vegetation around open water and is particularly uncommon. This habitat includes the Annex I habitat Molinia meadows on calcareous, peaty or clayey-silt- laden soils (Molinion caeruleae) H6410. In the UK these grasslands are represented by two NVC types: M24 and M26. M25 Molinia caerulea - Potentilla erecta mire was excluded from the definition of H6410, probably because it is considered a degraded bog-community. However, the more species-rich forms, particularly those that occur in intimate mosaics with M24 should be covered by the definition of H6410. M22 and M23 were excluded from the definition of H6410 as Molinia caerulea is either absent or a subordinate component of the vegetation. As far as the EUNIS classification is concerned, M22 & M23 appear to conform to E 3.4a moist/wet mesotrophic hay meadow and M24, M25 & M26